26   int &i; // expected-error {{union member 'i' has reference type 'int &'}}
70     bool has;  member
73     optional() : has(false) {}  in optional()
75     optional(U &&...u) : has(true), value(forward<U>(u)...) {}  in optional()
77     optional(const optional &o) : has(o.has) {  in optional()
78       if (has) new (&value) T(o.value);  in optional()
80     optional(optional &&o) : has(o.has) {  in optional()
81       if (has) new (&value) T(move(o.value));  in optional()
85       if (has) {  in operator =()
86         if (o.has)  in operator =()
90       } else if (o.has) {  in operator =()
93       has = o.has;  in operator =()
96       if (has) {  in operator =()
97         if (o.has)  in operator =()
101       } else if (o.has) {  in operator =()
104       has = o.has;  in operator =()
108       if (has)  in ~optional()
112     explicit operator bool() const { return has; }  in operator bool()
139 …licitly deleted because variant field 'struct (anonymous struct at{{.+}})' has a non-trivial defau…
158     non_trivial_constructor b; // expected-note {{has a non-trivial default constructor}}